@Article{Leutenegger15ijrr,
  author        = {S. Leutenegger and S. Lynen and M. Bosse and R. Siegwart and
                  P. Furgale},
  title         = {Keyframe-Based Visual-Inertial {SLAM} using Nonlinear
                  Optimization},
  journal       = {Int. J. Robot. Research},
  year          = 2015
}
